Multiple beam laser system for forming stents

Abstract

A system and method for precision cutting using multiple laser beams is described. The system and method includes a combination of optical components that split the output of a single laser into multiple beams, with the power, polarization status and spot size of each split beam being individually controllable, while providing a circularly polarized beam at the surface of a work piece to be cut by the laser beam. A system and method for tracking manufacture of individual stents is also provided.

What is claimed:  
     
       1. A laser system having a plurality of laser beams generated from an output of a single laser for cutting patterns into a plurality of stents at the same time, with each of the plurality of laser beams being controllable to produce a desired power, polarization and spot size and each laser beam directed at a separate stent work piece, comprising:
 a laser capable of emitting a first linearly polarized laser beam; 
 a first beam splitter capable of transmitting and reflecting the first linearly polarized laser beam into a second linearly polarized laser beam and a third linearly polarized laser beam; 
 a second beam splitter capable of transmitting and reflecting the second linearly polarized laser beam into a fourth linearly polarized laser beam and a fifth linearly polarized laser beam; 
 a third beam splitter capable of transmitting and splitting the third linearly polarized laser beam into a sixth linearly polarized laser beam and a seventh linearly polarized laser beam; 
 a half wave plate disposed in an optical path of each of the fourth, fifth, sixth and seventh laser beams, the half wave plate being capable of being rotated to alter the polarization direction of each laser beam; 
 a polarizer disposed in the optical path of each of the fourth, fifth, sixth and seventh laser beams for adjusting the laser power of the laser beam at a selected polarization direction; 
 an adjustable beam expander disposed in the optical path of each of the fourth, fifth, sixth and seventh laser beams to adjust the size of the laser beam; 
 a quarter-wave plate disposed in the path of each of the fourth, fifth, sixth and seventh laser beams after the beam splitter and any intervening mirrors for introducing circular polarization into the laser beams; and 
 a focusing lens for focusing each of the fourth, fifth, sixth and seventh laser beams to a desired spot size; and 
 wherein a circularly polarized beam spot for each of the fourth, fifth, sixth and seventh laser beams is controlled to accurately cut the stent pattern into the stent work piece upon which each of the fourth, fifth, sixth and seventh laser beam impinges. 
 
     
     
       2. The laser system of  claim 1 , wherein the optical path traveling downstream for each of the fourth, fifth, sixth and seventh laser beams includes in order the half wave plate, the polarizer, the adjustable beam expander, the quarter wave plate and the focusing lens. 
     
     
       3. The laser system of  claim 2 , wherein the spot size is individually controlled for each of the fourth, fifth, sixth and seventh laser beams by individual adjustment of the respective beam expanders and focusing lenses. 
     
     
       4. The laser system of  claim 3 , wherein for each of the fourth, fifth, sixth and seventh laser beams, a modulator and a switch are used to independently control the repetition rate, power level and on/off control of each laser beam.